Is it ensure, insure, or assure?
|strange quark |
A quark with an electric charge of -1/3 and a mass of 391 electron masses, greater than that of the up quark and down quark, but smaller than that of other quarks. The presence of a strange quark contributes strangeness of -1 to the physical system containing it, while a strange antiquark contributes strangeness of +1. See Table at subatomic particle.